Cord lock for venetian blinds



Nov. 20, 1951 RO N A 2,575,395

CORD LOCK FOR IEINETIAN BLINDS Filed Sept. 13, 1948 INVENTOR HARRY S. ROSENBAUMU Patented Nov. 20, 1951 UNITED STATES PATENT OFFICE 2,575,395 ooRii LOCK Fort vEN'E riAN BLINDS hairy "S. Rosenbaum, Baltimore, Md. Application September 13, 13 1s, si-i'al N6."49,04'3 main. c1. 24:134.)

, My inventionrelates to cord locks and more particularly to looks suitable. .for graspingand holding the cords or ropes of Venetian blinds by which the. blinds areraised and lowered. H'e'reto 9 9 d n k f x Vs iiah dsf tly been designed, to grasp thefcor ds by means of a toothed dog movable in "an are which intersects the line of travel of the, cords and forces them against a housinggforthe, lock through which the cords pass. The dog is swung into locking position by a person pulling the ropes against the toothed edge of the dog and at the same time allowing the blinds to lower slightly. This operation causes severe fraying of the cords due to slippage of the cord across the teeth of the dog, before the teeth bite sufliciently into the cord to hold it against the lock housing. Also in looks heretofore used the cords have had a tendency to twist which promotes further slippage and fraying.

I have invented a cord lock for Venetian blinds whereby the aforementioned objections are overcome. By my invention cord slippage and fraying is reduced to a minimum and in addition the cords are prevented from twisting.

My cord lock comprises a frame through which the Venetian blind cords are adapted to pass. A locking means is pivoted in the frame and is adapted to be swung into engagement with the cords to press and lock them against the frame. The locking means is forced into contact with the cords by means of a cantilever latch pivoted to the frame in such manner that pulling the cords against a cord guide forming one end of the latch causes the opposite end to raise the locking means into locking position.

In the drawings illustrating a presently preferred embodiment of my invention Figure 1 is a vertical section on the line [-4 of Figure 2;

Figure 2 is a top plan view of the cord lock of my invention;

Figure 3 is a bottom plan view of the cord lock of my invention;

Figure 4 is a section along the lines IVIV of Figure 1;

Figure 5 is an end view from the left, viewing Figure 1;

Figure 6 is a side elevation;

Figure 7 is a section on the same line as Figure 1 showing the cord in locked position.

Referring first to Figure 1, I have illustrated a cord lock consisting of a frame I, here shown as a channel, through which a plurality of cords 2 are adapted to pass. The channel I has an inwardly extending projection 3 formed by bendifig the'top of the frame 'I and against which the cords 2 may be clamped by the dog 4 which is pivoted about a shaft 5 extending through the side walls of the channel at a point below the inward"- ly curved surface. The base of the dog 4 has a projecting lip 6 which is toothed or serrated to clamp the rope. A lever, or cantilever latch, 1, is pivoted about a shaft 8 in the side walls of the frame i. The latch U-shaped in section, the arms of the U lying *outside the sides of the frame.

A pulley H], having grooves equal in number to the number of cords, is also rotatably mounted on the shaft 8. The cords 2 pass over these pulleys if) and through an opening H in one end of the cantilever latch I. This opening, which is of dimensions such that the cords may pass therethrough only when parallel to each other in a plane parallel to the shaft 8 of the pulleys, acts as a cord guide and as a bearing surface against which the cords may be pressed to cause the opposite end of the cantilever latch to rotate about the shaft -8 and lift the dog 4 against the cords.

The lock is secured at one end to the head rail of Venetian blind. The blind is raised and lowered by the cords 2 which pass through the head rail and downwardly through the opening II in the latch l to a convenient point. When the cords are drawn directly downward, the Venetian blind is raised and, conversely, permitting the cords to move upward causes the Venetian blind to be lowered. If the cords are drawn to the left, viewing Figure 1, they rotate the cantilever latch i about the shaft 8 and raise the dog 4 causing the teeth on the lip 6 to bite into the cords and clamp the cords against the inwardly projecting surface 3 (see Figure 7). Rotation of the dog 4 by the latch 1 causes the teeth on the dog to take a practically instantaneous bite on the cords. This minimizes slippage between the teeth and cords and thus reduces fraying of the cords. The lock continues to hold the cords until they are again drawn downward, whereupon the dog is drawn away from the inwardly curved surface, disengaged from the cords and falls back into contact with the cantilever latch in the position shown in Figure l.

The cord lock of my invention has numerous advantages over cord looks of the prior art. The most important of these advantages are the (1) positive locking action which eliminates slipping, (2) freedom from fraying of the cords and, (3) freedom from twisting and knotting of the cords.

7 low head rail through which blind raising and lowering cords pass in a generally horizontal direction, said lock comprising an elongated inverted U-shaped housing adapted to be inserted in a horizontal position within the head rail, a projection in the top of the housing extending downwardly from the housing, a pulley rotatably mounted on a shaft in the housing and over which said cords pass and then extend downwardly, a cord locking dog pivotally mounted at one of its ends in the housing and adapted on rotation to engage the cords with its free end and press them against the projection, an elongated lever U-shaped in cross section, pivotally mounted adjacent the center of itssides on the same shaft as said pulley with its base extending in a horizontal plane below said pulley, one end of the base extending under and supporting the free end of said locking dog when the dog is not 4 cords pass, whereby a pull at an angle to the vertical but generally parallel to the blind on the vertically extending portions of the cords will rotate the lever causing it to turn the locking dog against the cords to engage them and press them against the projection, and whereby upon release of the vertical portions of the cord the lever will rotate away from the dog in its cord locking position.

HARRY S. ROSENBAUM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,203,715 Doust Nov. 7, 1916 1,363,902 Lueckenbach Dec. 21, 1920 1,710,697 Gilbert Apr. 30, 1929 1,951,528 Pearson Mar. 20, 1934 2,010,286 Wiener et a1 Aug. 6, 1935 2,012,856 Latham Aug.-27, 1935' 2,075,214 Lorentzen Mar. 30, 1937 2,115,796 Bradfield May 3, 1938 2,175,977 Stuber et al. Oct. 10, 1939 FOREIGN PATENTS Number Country Date 452 Great Britain Feb. 4, 1874 

